Fuel Quality Testing for the Fleet Manager

By Steve Wallace | March 17, 2008
When Fleet Biodiesel made its debut at the 2006 Alternative Fuels & Vehicles Conference, it was in the business of helping fleets make the transition to biodiesel fuel. During those few days company officials learned a lot about biodiesel from the folks who were really using it. The company was bombarded by questions about biodiesel quality and listened to fleet managers who had postponed or even reversed their decision to use biodiesel because of quality concerns. It was clear that the basic formula for successfully re-powering a vehicle fleet on biodiesel would take into account the issue of fuel quality.

As a result of that conference, Fleet Biodiesel changed course and plunged full force into the fuel testing arena, setting out to develop tools that would allow fleet managers to verify the quality of their fuel. In April 2007, the company launched the first of its family of field test kits for biodiesel and petroleum diesel fuel. The company still helps fleets make the move to biodiesel, but it now focuses on fuel quality verification to make sure the biodiesel experience is a positive one.

The basic recipe for switching to biodiesel is no secret. Potential users are fortunate that the fuel has been in use for quite a while and its pitfalls are well documented. This article is not meant to be a primer for fleet managers making the transition, but will cover some of the basic considerations and current issues that need to be addressed. The biodiesel transition model divides the process into three phases: preparation, fuel sourcing and maintenance.

It doesn't take much to convert a fleet to biodiesel, but one needs to be thorough during the preparation process. Most of the preparation tasks are simple and inexpensive, whether it's installing desiccant vent traps on storage tanks or changing out the old hoses in vintage dump trucks. Make sure this is done at the beginning before biodiesel is introduced. Many fleets that experience difficult transitions can trace their problems back to something fairly obvious-like deciding not to clean out a storage tank before switching fuels.

Most of the preparation process is documented on a number of Web sites. The National Biodiesel Board (www.biodiesel.org), the National Renewable Energy Lab (www.nrel.gov), and the U.S. DOE (www.eere.energy.gov) are all excellent resources. Regional Clean Cities Coalitions, the West Coast Collaborative and local biodiesel user groups provide additional support to fleet managers moving to alternative fuels.

Several preparation tasks are normally expected. First, the fleet should be screened for pre-1995 vehicles. Second, storage tanks and dispensers should be evaluated for biodiesel compatibility. Third, environmental factors (e.g., weather) should be examined for biodiesel suitability. Fourth, plans should be developed for incorporating biodiesel in seasonal- and emergency-use vehicles and generators. Fifth, storage tanks should be prepped and older vehicles refitted with biodiesel-compatible hoses and gaskets. Finally, compliance with local emissions standards must be ensured.

The preparation process will vary greatly depending on the specific circumstances of the fleet. If this seems intimidating, remember that preparation is a one-time exercise and that there are many fleets that have made the switch with older vehicles operating in extremely adverse conditions. Peterson Air Force Base in Colorado and Mammoth Mountain Ski Resort are two examples.

Fuel Sourcing
Most of the problems related to using biodiesel are due to quality. Fortunately, the vast majority of biodiesel fuel being produced and distributed is good fuel that meets ASTM specifications before blending. Remember that one doesn't have to use biodiesel to have fuel-related problems. Water is a problem for petroleum diesel, which can degrade if it sits in a tank for one year.

Biodiesel burns like petroleum diesel, but it is not petroleum diesel. As tempting as it may be, don't think of it that way. Petroleum is highly regulated, produced in enormous quantities and subject to much less variation during the production process. "Highly regulated" means that it is tested to specification during production and transportation to market-an expensive proposition unless testing is conducted in very large quantities. On the other hand, biodiesel is much more loosely regulated. It is typically produced in smaller quantities and subject to a number of quality-affecting factors including the feedstock used and the way it is transported to market. Petroleum is typically transported via pipeline while biodiesel is shipped via tanker truck and railcar.

To complicate matters, the positive characteristics of biodiesel, such as its lower emissions profile and non-toxic nature that make it an excellent alternative fuel, are also responsible for its notorious variation in quality. It is biodegradable and-like the plants it often comes from-is more susceptible to incidental chemical interactions and microbial contamination. The bottom line is that the quality of biodiesel fuel produced to ASTM D 6751 specifications can change anywhere along the journey from the producer to the engine that burns it.

So, how do fleet managers make sure they get good fuel? The first step is to ensure the distributor understands how to handle biodiesel. Obvious signs to look for include BQ-9000 certification and a good track record. However, these aren't always available. Develop a checklist for the distributor to help identify the vendors that are quality conscious and most likely to provide good fuel. Some key questions that should be asked include:

How does the distributor verify fuel quality from its supplier?

Does the supplier use a consistent feedstock?

Are additives used to compensate for seasonal conditions?

What method is used to blend the biodiesel fuel with petroleum diesel?

Does the distributor have dedicated storage tanks and trucks for biodiesel?

Does the distributor periodically test its biodiesel tanks for fuel degradation?

Will the distributor provide assistance when bad fuel is suspected or discovered?

Is the distributor willing to cooperate with the fleet's quality assurance program?

The answers to these questions may lead to more questions, but they will certainly provide an idea of the distributor's familiarity with biodiesel. In many cases, distributors will revise their handling practices to meet your requirements. If asked, they may even implement a fuel quality assurance program. Colorado Petroleum instituted a quality testing program for its client, Amphitheater Public Schools in Arizona. Once the fuel has been sourced, the fleet manager should plan periodic audits to make sure the distributor is performing as advertised.

Now that the fleet is prepared and the fuel is sourced, it's time for the final phase of the transition.

The maintenance phase has nothing to do with maintaining vehicles-though one should anticipate some minor vehicle maintenance after switching to biodiesel. Remember that most problems arising from biodiesel use are related to fuel quality. That quality can change at any point between the producer and the fuel injectors. Verifying fuel quality on site can eliminate these problems by testing the fuel as it comes from the distributor, out of the pump and, if necessary, in the equipment itself.

In our experience, a fuel delivery from a distributor is the most likely cause of drastic changes in fuel quality. This is because biodiesel degrades relatively slowly over time, whereas a bad fuel drop from the distributor can have an immediate and much larger effect. Ask a fleet manager who has been burning B5 for a couple of years and gets a load of B100 in his or her tanks. In this case, too much of a good thing is not so good. Luckily, this type of problem is easy to fix once detected.

So how do fleet managers verify fuel quality before it goes into their vehicles? Laboratory testing would be great if one has the budget and the time to wait for the results. In our experience, this is a rare set of circumstances. Periodic lab testing would be another option, but it wouldn't catch the occasional bad batch of fuel-the one that stops vehicles. The ideal situation allows for fuel to be tested reliably and quickly where it's being used. Fortunately, several options exist for on-site quality testing: field test kits, portable lab instruments and full-fledged laboratory instruments. A brief description of each of these options and the associated costs follow.

Field test kits have been around for years, but are only now addressing the needs of fleet managers. They typically cost between $3 and $25 per test. Tests are available for a variety of key indicators of fuel quality, such as water content, acid number, microbial contamination, glycerin content and percentage of biodiesel. Field tests are typically inexpensive and easy to perform (e.g., pour the fuel into a bottle and shake it to get results). They provide an excellent screening mechanism to detect bad fuel or may be used as a diagnostic tool for discovering how a fuel is out of spec. The drawback for these tests is that they are usually limited to a "go/no-go" result. In other words, they won't provide an exact measurement of the key indicators as does an analytical laboratory test.

Portable lab instruments are smaller, more rugged versions of the instruments found in an analytical laboratory. They typically cost between $3,000 and $25,000 per instrument. Many operate on battery power, so they can be used wherever testing is needed. These instruments are typically focused on one particular fuel quality characteristic, like percentage of biodiesel or water content. Portable instruments are often more difficult to use than field test kits, but they provide more accurate (nearly lab-quality) results.

Recently, several multifunction instruments have been introduced to the market that use infrared technology. Like field test kits, these instruments do not use the ASTM testing protocols, but are easy to use and give accurate results. Key indicators tested include free and total glycerin, percentage of biodiesel, water content, free fatty acids and cloud point.
Laboratory instruments typically cost between $4,000 and $70,000 per instrument. This is the ultimate testing option for fleet managers who have large budgets, laboratory workspace and a technical staff. Like the portable instruments, lab instruments are usually "one-trick-ponies." Each instrument can only test for one key indicator. The advantage is that the results are high quality and are derived using the official ASTM protocols.

Fleet managers are the heroes of the biodiesel industry. They are the ones who make the greatest impact on the environment by their selection of alternative fuels. They are also the ones who have the most at stake in terms of operational risk. A fuel problem can be stressful for an organization's budget and for the maintenance team.

Fleet managers must carefully prepare for the transition to biodiesel, be selective in choosing a fuel vendor, and develop a sensible fuel quality assurance program to verify and document fuel quality on a regular basis. Most fleet managers will have the best results by using a combination of field-testing (using a test kit or portable lab instrument) and periodic lab testing. The field tests will increase the likelihood of catching bad fuel before it does any damage, and lab testing will catch more subtle problems before they trigger the field tests. This type of program costs very little but provides substantial protection against bad fuel.

Steve Wallace is president of Fleet Biodiesel, a company he founded with Ken Snoke in 2005 with the goal of promoting biodiesel use in the southwestern United States. Reach Wallace at swallace@fleetbiodiesel.com.
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